Also used in some cases as a more general purpose negative exclamation, nearly always referring to a lack of something. For example, if something particularly unlucky happened to someone, a friend might be heard to exclaim "brass!".

Brass also specifically refers to the cylindrical shell casing around a bullet. Once a shooter fires a gun, the bullet leaves, the gunpowder burns up, and the brass is what's left. Brass is mostly made of brass.

An alloy (usually yellow) of copper and zinc, in variable proportion, but often containing two parts of copper to one part of zinc. It sometimes contains tin, and rarely other metals.

2. Mach.

A journal bearing, so called because frequently made of brass. A brass is often lined with a softer metal, when the latter is generally called a white metal lining. See Axle box, Journal Box, and Bearing.